Lamp and operating circuit



Oct. 21, 1 41. DSGUSW 2;259,954

LAMP AND OPERATING CIRCUIT Filed Nov. 30, 1938 age/Ty 42 \l 43 I rum-0mm R620) 7 5 g LINE INVENTOR 17.5. GUST/N.

ATTORNEY Patented Oct. 21,1941 I UNITED 2 STAT ES PATENT OFFICE iazsaosi LAMP AND OPERATING cmcurr- Daniel S. Gus'tin, Bloomfield, N. 3., assignor to Westinghouse Electric 3; Manuiacturing Company, East Pittsburlh. Pa., a corporation of Pennsylvania This invention relates to lamps and operating circuit, and particularly to ultra-violet lamps of the gaseous conduction type, in which the bulb is provided with a window of extremely thin glass for efliciently transmitting the generated light.

One of the principal objects of my inve on, generally considered, is the provision of a thinwindow, ultra-violet lamp, operating at a lower temperature than those previously on the market without reduction in output, having. a' longer life and a not much greater wattage, and being and labor cost, with less shrinkage.

Another objector my invention is the provi-\ .sion of an ultra-violet lampof, the thin window type, having a greater stability and a more uniform output, and capable of being burned in any position and with equal efllciency.

A further object of my invention sion of a thin-window,-ultra-vio1et lamp, so constructed that it is less affected by surrounding atmospheric conditions than previous lamps of this type, may be manufactured at smaller cost,

and is operable on a double, rather than a single" ci'rcuiti. thereby giving full-wave generation of energy. j

is the provi- I capable of manufacture at a smaller material tion, comprises a bulb l2, formed of glass pervious to ultra-violet light, provided with a base 13 from which contact prongs l4, l5, l6, and" extend. A stem l3, extends from the neck IQ of the bulb and encloses lead-in conductors 2| to 24,. inclusive, extending respectively from the contact prongs l4 to 11 inclusive.

Lead-in conductors 2| and 22 connect, respectively, with supports 25 and 26, on which are.

mounted the electrodes 21 and 23, which function as the anodes of the lamp. These electrodes are desirably formed from rectangular plates of nickel, or other similar material, bent to cylindrical form to partially enclose the space occupied by the electrode 29. The electrode 29 is mountedon supports 3| and 32,- respectively extending from lead-in conductors 23 and 24,

A still further" object "of my invention is the provision of an ultra-violet lamp of the gaseousconduction type, comprising a pair of cylindrically curved anodes, partially enclosing a heated cathode disposed therebetween, and spaced in a direction transverse to the longitudinal axis of the bulb, a gaseous filling in saidbulb admixed with mercury vapour, said bulb having a terminal substantially spherical portion in which is formed a re-entrant bulbous portion, disposed substantially co-axially with the bulb, having its inner part verythin, disposed near-to the electrodes, and. lying generally parallel to the path of the discharge produced therebetween, for ef-' ficiently transmitting the ultra-violet light pro duce'd.

Other objects relating-to the particular arrangement and construction of the various parts, will become ap-,

' parent as the description proceeds.

Referring to the drawing: Figure 1 is a partial elevational and partial vertical sectional view of a lamp embodying my invention, also: showing circuit. I

Figure 2 is an enlar ed horizontal sectional view of the line 11-11 of Figure 1', in the direction of the arrows.

Referring to the drawing a preferred operating in detail, the lamp and advantages of theinventio'n,

which serve to transmit heating current to said electrode which functions as the hot cathode of "the lamp. It will thus be seen that the members 25, 3|, 32 and 26 are alined along the top of-the stem II or press, and the horizontal plane through the middle of the anodes 21 and 28 includes the axis oi the cathode'29.

The electrode 29 is desirably formed or a tungsten wire or filament 33 "about which nickel wire 34 is coiled, and the whole again formed into a secondary coil 35 as illustrated most clearly in Figure 2. The nickel wire coating on the coil is, in turn, coated with electron-emission material, such as 'a mixture of the oxides of barium and strontium, or other alkaline earth oxides, as will be understood.

In order to efiiciently transmit the ultra-violetlight generated when a discharge is produced from the cathode 29 to the anodes 21 and 28, the bulb i2 is formed with a reentrant bulbous portion 36, preferably substantially spherical and lying on the longitudinal axis of the bulb 12, that is substantially coaxial with said bulb with its inner portion very thin, lying close to the elec trodes, and extending approximately parallel, or

uniformly spaced with respect to the line of dislustrated in Figure l. The thickness oi the window 36. adjacent the electrodes, is desirably maintained between .002" and .003", tapering from the periphery where it Joins the imain spherical end portion of the bulb l2.

After assembling the bulb with the electrodes, exhausting and filling it with an inert gas. such as about '5 mm. of pure argon, and a drop (about 200 mg.) of mercury, the lamp may be operated and 28 until after it has been h'eatedto operat-'' ing temperature. For this reason, the circuit through the line 44 to the center tap of the secondary winding 39, is not completed by closing the switch or time-delay relay 45, .until after the connection with the line has been made for a sumcient length of time to heat the cathode 29 to operating temperature. I

In other words, the procedure of putting the lamp into, service is to first close the line switch untilthe cathode reaches operating temperature, and then close the switch or relay 45. If a time-delay relay is employed, it, of course, may be formed as a part of the line switch (not shown) so that the cincuit through 44 is notcompleted until the cathode 29 has been heated to the desired temperature. From the foregoing disclosure it will be seen cury vapour lamp than previous constructions,

that I have provided a better thin-window mersaid lamp consisting of two anodes and a cathode, the cathode being desirably nickel wire wound over tungsten and, coated with a mixture of oxides of barium and strontium. The cathode, in a preferred embodiment, is desirably operated by a current of about eight amperes having a potential of about two volts. The open circuit potential across the anodes, in such an embodiment of the invention, may be forty-four volts; with the lamp, when operating, drawing about one ampere from the center tap through the conductor 44 and the voltage across, the

anodes dropping to about fourteen.

Tests on lamps such as disclosed, have shown that after 200 hours burning a relatively small drop in initial output occurs, while previous constructions have shown a much greater loss in eftherebetween,

means for heating said cathode, and a gaseous filling in said bulb admixed with mercury vapor, said bulb having a thin window portion disposed close to said electrodes and lying in a plane disposed approximately parallel to the line of discharge in said bulb.

8. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes spaced in a direction transverse to the longitudinal axis of said bulb and presenting concave surfaces to one another, a cathode dis-.

posed therebetween, means for heating said cathode, a gaseous filling in said bulb admixed withmercury vapor, and a re-entrant bulbous portion, substantially coaxial with said bulb, extending from an end of said bulb toward said electrodes, the inner part of said re-entrant portion being very thin for efilciently ultra-violet light.

4. An ultra-violet lamp of 'the gaseous-conduction type "comprising an enclosing envelope, a pair of anodes, a'cathode disposed therebetween,

transmitting said anodes being curved to partially enclose said.

cathode, means for heating said cathode, a gaseous filling in said envelope admixed with mercury vapor, said envelope having a base and a terminal substantially spherical portion, and a re-entrant bulbous ultra-violet light.

v 5. An ultra-violet lamp of the gaseous-com, I an enclosing envelope, a pair of electrodes adapted to function as electrode disposed duction type comprising anodes, an intermediate said anodes consisting of plates bent to partiallyenclose said cathode, means for heating said intermediate electrode to cause it to function as a cathode, a gaseous filling in said envelope admixed with mercury vapor, and a reentrant bulbous portion extending from an end of said envelope toward said electrodes and dis- Although a preferred embodiment of my in- I vention has been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

1. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of arcuate anodes concave toward one another, a cathode disposed therebetween, means for heating said cathode, a gaseous filling" in said bulb admixed with. mercury vapor, 'and a re-entrant bulbous portion extending from an end of said bulb toward said electrodes, the inner part of the said re-entrant' portion being very thin, lying close to the electrodes and extending approximately parallel to the line of dischargev therebetween, for efficiently transmitting ultraviolet light produced.

2. An ultra-violet lamp of the gaseous-conduction type comprising a bulb, a pair of anodes posed substantially co-axially with said envelope,

' the inner part of said re-entrant portion being thin enough to emciently transmit ultra-violet light.

6. An ultra-violet lamp. of the gaseous-conduction type comprising an enclosing envelope,

a pair of anodes concave towards each other, a cathode disposed therebetween, means for heating said cathode, a gaseous filling in said envelope admixed with mercury vapor, anda re-entrant bulbous portion extending from an end of said envelope toward said electrodes, the inner part of said re-entrant portion being very thin and disposed close to said electrodes for efilciently transmitting ultra-violet light produced thereby.

7. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing envelope,

a pair of curved electrodes ,concave toward each other and adapted to function as anodes, an intermediate electrode disposed therebetween and partly enclosed thereby, means for heating said intermediate electrode to cause it to emit electrons, a gaseous filling in said envelope admixed with mercury vapor, and a re-entrant bulbous portion extending from an end of said envelope towards said electrodes, the inner part of said re-entrant portion being very thin, lying generally parallel to the path of discharge producible between said electrodes, and efflcientlytransdisposed therein and curved concavely toward 3 one another, a cathode positioned therebetween,

such a discharge.

mitting ultra-violet light which is part extending from saidv spherical portion toward saidelectrodes, coaxj ially with said envelope, the inner portion of said re-entrant part being very thin for transmitting generated by' 8. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes concave toward one another, a cathodedisposed therebetween, means ior heating said cathode to cause it to emit electrons, argon in said bulb admixed with mercury vapor, and a reentrant portion extending from an'end of said bulb toward said electrodes, the inner part of said re-entrant portion being suiiiciently thin to efficiently transmit ultra-violet light generated by a discharge between said electrodes.

9. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes spaced in a direction transverse to the longitudinal axis of said bulb, a cathode disposed therebetween, said anodes being bent to more completely surround saidcathode, means for base and a terminal substantiallyspherical portion, a re-entrant bulbous part extending from said spherical portion towards said electrodes and disposed substantially co-axially with said bulb, the inner/ portion of said re-entrant part being very thin, disposed near to said electrodes and lying generally parallel to the path of discharge produced therebetween, for efilciently transmitting the ultra-violet light produced.

10. Any ultra-violet lamp of the gaseous-conduction type comprising an enclosing envelope, a

pair of electrodes spaced in a direction transverse tothe longitudinal axisof said envelope and designed to act as anodes, an intermediate electrode disposed therebetween, said anodes being curved so as to more completely-surround said cathode,

other to more completely enclose said intermediate electrode, and means for operating said lamp comprising a transformer, a supplemental heating said cathode, a gaseous filling in said bulb admixedwith mercury vapor, said bulb having a means for heating said'intermediate electrode to cause it to emit electrons and act as a cathode, a

filling of argon at a pressure of about 5 mm. and admixed with mercury vapor, said envelope having a base at one end and a susbtantially spherical portion at the otheriend, said spherical por-' tion being formed with a re-entrant part extending toward the electrodes and disposed substantiallyco-axially with said envelope, the inner portion of said re-entrant part being very thin, disposed near to said electrodes, and lying generally parallel to the path of discharge which may be, produced therebetween, for emciently transmitting ultra-violet light.

11. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes formed concave toward one another, a cathode disposed therebetween, a gaseous filling I in said bulb admixed with mercury vapor, and a re-entrant bulbous portion extending from an end of said bulb toward said electrodes, the inner part of said re-entrant portion being very thin to provide for the transmission of ultra-violet light.

12. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes, each consisting of a plate bent to more completely enclose the space therebetween, a cathode disposed therebetween, said cathode comprising a tungsten wire in helical form over which is wound a nickel wire coated with electron-emitting oxides, means for introducing current to said tungsten wire for heating the cathode to electron-emitting temperature, a gaseous filling in said bulb admixed with mercury vapor and a reentrant portion extending from an end of said trica'l connections only between the main sec- 7 winding on said transformer, electrical connections only between the main secondary winding terminals of said transformer and said first men.-

tioned electrodes, and between said supplemental winding and the terminals of said intermediate electrode to heat it to electron-emitting temperature, and means for connecting said supplemental secondary winding to the mid-point of the main secondary winding when the intermediate electrade has reached, operating temperature, in order to then cause it to function as a cathode with the associated electrodes as anodes, independent of any temporary starting means.

15. An ultra-violet lamp of the gaseous-conduction type comprising an enclosing bulb, a pair of anodes formed concave cathode disposed therebetween,

said bulb admixed with a gaseous filling in of said bulb toward said electrodes, the inner part of said re-entrant portion being very thin to provide for the transmission of ultra-violet light, and

means for operating said lamp, comprising a transformer having a supplemental winding, elecondary winding terminals of said transformer and said anodes, and between said supplemental winding and the terminals of said intermediate electrode to heat it to electron-emitting temperature, and means whichconnect said supplemental secondary winding to the mid-point oi the main secondary winding when the intermediate electrodehas reached operating temperature, in order to then cause it to function as a cathode with the bulb toward said electrodes, the inner part of 13. An ultra-violet lamp of the gaseous-conassociated electrodes as anodes, independent of any temporary starting means.

16. In combination, a lamp of the gaseous conduction type comprising an enclosing envelope, an electrode adapted to function as an anode, an electrode comprising a filament, and means for operating said lamp comprising a transformer, a supplemental winding on said transformer, an electrical connection between amain secondary winding terminal of said transformer and said first-mentioned electrode, electrical connections between the terminals of said supplemental winding and said filamentary electrode to heat it to electron-emitting temperature, and normally open switch means for connecting said supple mental secondary winding to the main winding when the filamentary electrode has reached operating temperature, in order to only thencause it to function as a cathode with the first mentioned electrode as ananode, independent of any temporary starting means.

DANIEL s. Guam.

toward one another, a-

mercury vapor, a reentrant bulbousfportion extending from an end I 

